1. Field of the Invention
The invention relates to transmission systems for transferring rotational motion from a prime mover to a load, and more specifically to transmission systems having continuously variable power/speed transmission ratios dependent on and automatically adjustable as a function of the operational conditions of the system. In terms of utility, the transmission system according to the present invention is particularly, but by no means exclusively, useful in the automotive industry, to replace any and all types of the presently used, so-called "Automatic Gearing Transmissions". However, the transmission system will also be most efficient in other, non-vehicular installations, whether requiring variable ratios or not.
2. Prior-Art Background
It seems advisable to commence this discussion by listing the general objectives that should be attained through the exploitation of this invention, and for this purpose there should be first noted the main requisites that are to be satisfied by an ideal transmission system, namely:
(1) Highest possible efficiency of power transmission over all applicable load ranges;
(2) Capability of handling extreme changes in output/input power during normal operation of the motor/load, respectively.
(3) Protection of the motor in cases of overloading and capability of braking the load to instantaneous "dead stop" without causing damage to the motor; (4) Smooth gradual increase and decrease of input power and elimination of shocks and vibrations;
(5) Capability of utilizing the motor as speed retarding element of the system;
(6) Simple, inexpensive and highly reliable construction; and
(7) Convenient installation, maintenance and repair of the system.
To attain as many as practicable of the above listed features, great efforts have been expended in the development of automatic transmission systems, especially, if not exclusively, for motor vehicle purposes.
Before proceeding with the description of the state of the art, and for the better understanding and evaluation thereof, few basic terms and devices should be briefly discussed.